"

 COPYRIGHT (c) 1994 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libview2' }"

"{ NameSpace: Smalltalk }"

ImageReader subclass:#PCXReader

	instanceVariableNames:'header buffer nBuffer bufferIndex sourceBytesPerRow depth nPlanes'

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Images-Readers'

!

!PCXReader class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1994 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    this class provides methods to load PCX bitmap files.

    PCX used to be a popular image format in the early PC times,

    but became almost obsolete in the meantime.

    This reader is not tuned and performs slow on non-8bit images;

    if at all, use it to convert old image files to newer formats,

    such as png, tiff or jpg.

    Due to not having too many examples for testing, 

    this could fail to read some files. 

    (especially, I have no uncompressed files for testing).

    Only 1,2,4,8 and 24-bit PCX images are supported.

    Image writing is not.

    [See also:]

        Image Form Icon

        BlitImageReader FaceReader GIFReader JPEGReader PBMReader 

        ST80FormReader SunRasterReader TargaReader TIFFReader WindowsIconReader 

        XBMReader XPMReader XWDReader 

"

!

examples

"

                                                        [exBegin]

    Image fromFile:'/usr/share/lilo/suse_640x480.pcx'

                                                        [exEnd]

                                                        [exBegin]

    Image fromFile:'../../goodies/bitmaps/pcxImages/lena_depth8_palette.pcx'

                                                        [exEnd]

"

! !

!PCXReader class methodsFor:'initialization'!

initialize

    "tell Image-class, that a new fileReader is present

     for the '.pcx' extension."

    MIMETypes defineImageType:'image/x-pcx'  suffix:'pcx' reader:self.

    "Modified: 27.6.1997 / 18:39:23 / cg"

! !

!PCXReader class methodsFor:'testing'!

isValidImageFile:aFilename

    "return true, if aFilename contains a PCX image"

    |count header inStream|

    inStream := self streamReadingFile:aFilename.

    inStream isNil ifTrue:[^ false].

    inStream binary.

    header := ByteArray uninitializedNew:128.

    count := inStream nextBytes:128 into:header.

    inStream close.

    ((count == 128) and:[self isValidPCXHeader:header]) ifFalse:[

	^ false

    ].

    ^ true

    "Modified: 17.9.1995 / 17:32:07 / claus"

!

isValidPCXHeader:aHeader

    "return true, if aHeader looks like a PCX image header"

    "check magic number"

    ((aHeader at:1) ~~ 16r0A) ifTrue:[

	^ false

    ].

    "check version"

    (#(0 2 3 5) includes:(aHeader at:2)) ifFalse:[

	^ false

    ].

    ^ true

    "Modified: 16.4.1997 / 22:24:32 / cg"

! !

!PCXReader methodsFor:'private-reading'!

extractColorMap16

    "extract the 16-entry colormap from the header"

    |rawMap|

    rawMap := header copyFrom:17 to:(17 + (16*3) - 1).

    ^ MappedPalette rgbBytesVector:rawMap 

!

nextByteFromBufferOrStream

    |byte|

    nBuffer ~~ 0 ifTrue:[

        byte := buffer at:bufferIndex.

        bufferIndex := bufferIndex + 1. nBuffer := nBuffer - 1.

    ] ifFalse:[

        byte := inStream next

    ].

    ^ byte

!

readColorMap256

    |rawMap mapSize|

    rawMap := ByteArray uninitializedNew:(256*3).

    nBuffer ~~ 0 ifTrue:[

        mapSize := buffer size - bufferIndex + 1.

        mapSize := mapSize min:(256*3).

        rawMap replaceFrom:1 to:mapSize with:buffer startingAt:bufferIndex.

        nBuffer < (256*3) ifTrue:[

            inStream nextBytes:((256*3)-nBuffer) into:rawMap startingAt:nBuffer+1

        ]

    ] ifFalse:[

        inStream nextBytes:(256*3) into:rawMap.

    ].

    ^ MappedPalette rgbBytesVector:rawMap 

!

readCompressedData

    |bendIndex rowStartIndex  endIndex byte nByte value idx2

     srcIndex dstIndex srcRowStartIndex dstRowStartIndex bytesPerPane planeData imageBytesPerRow|

    imageBytesPerRow := (((width * depth) + 7) // 8).

    bytesPerPane := height * (imageBytesPerRow max:sourceBytesPerRow).

    planeData := 1 to:nPlanes collect:[:planeNr | ByteArray uninitializedNew:bytesPerPane].

    data := planeData at:1.

    buffer := ByteArray uninitializedNew:4096.

    bufferIndex := 1.

    bendIndex := 1.

    rowStartIndex := 1.

    1 to:height do:[:row |

        1 to:nPlanes do:[:planeNr |

            |planeBytes|

            planeBytes := planeData at:planeNr.

            dstIndex := rowStartIndex.

            endIndex := dstIndex + sourceBytesPerRow.

            [dstIndex < endIndex] whileTrue:[

                bufferIndex == bendIndex ifTrue:[

                    nBuffer := inStream nextBytes:4096 into:buffer.

                    bufferIndex := 1.

                    bendIndex := nBuffer + 1.

                ].

                byte := buffer at:bufferIndex.

                bufferIndex := bufferIndex + 1.

                ((byte bitAnd:2r11000000) ~~ 2r11000000) ifTrue:[

                    planeBytes at:dstIndex put:byte.

                    dstIndex := dstIndex + 1.

                ] ifFalse:[

                    nByte := byte bitAnd:2r00111111.

                    bufferIndex == bendIndex ifTrue:[

                        nBuffer := inStream nextBytes:4096 into:buffer.

                        bufferIndex := 1.

                        bendIndex := nBuffer + 1.

                    ].

                    value := buffer at:bufferIndex.

                    bufferIndex := bufferIndex + 1.

                    idx2 := ((dstIndex + nByte) min:endIndex) - 1.

                    planeBytes from:dstIndex to:idx2 put:value.

                    dstIndex := dstIndex + nByte.

                ].

            ].

        ].

        "/ rowStartIndex := endIndex.

    ].

    nBuffer := endIndex - bufferIndex.

    "/ now merge the planes

    nPlanes > 1 ifTrue:[

        depth == 8 ifTrue:[

            (nPlanes >= 3) ifTrue:[

                "/ a simple rgb image

                nPlanes := nPlanes min:4.

                data := ByteArray uninitializedNew:(nPlanes*width*height).

                srcRowStartIndex := dstRowStartIndex := 1.

                1 to:height do:[:y |

                    1 to:nPlanes do:[:p |

                        |planeBytes|

                        dstIndex := dstRowStartIndex + (p - 1).

                        srcIndex := srcRowStartIndex.

                        planeBytes := planeData at:p.

                        1 to:width do:[:x |

                            data at:dstIndex put:(planeBytes at:srcIndex).

                            dstIndex := dstIndex + nPlanes.

                            srcIndex := srcIndex + 1.

                        ].    

                    ].

                    srcRowStartIndex := srcRowStartIndex + imageBytesPerRow.

                    dstRowStartIndex := dstRowStartIndex + (width * nPlanes).

                ].

            ].

            depth := nPlanes * 8.

            photometric := nPlanes==3 ifTrue:[#rgb] ifFalse:[#rgba].

        ] ifFalse:[

            (depth == 1) ifTrue:[

                |newDepth nPlanesUsed|

                nPlanesUsed := nPlanes min:4.

                newDepth := (nPlanesUsed * depth) nextPowerOf2.

                data := ByteArray new:((width*height*newDepth)+7)//8.

                srcIndex := dstIndex := 1.

                1 to:height do:[:y |

                    |inMask outBitCount outBits|

                    inMask := 16r80.

                    outBitCount := 0.

                    outBits := 0.

                    1 to:width do:[:x |

                        1 to:nPlanesUsed do:[:p |

                            outBits := (outBits bitShift:1).

                            (((planeData at:p) at:srcIndex) bitAnd:inMask) ~~ 0 ifTrue:[

                                outBits := outBits bitOr:1.

                            ].

                        ].

                        outBits := outBits bitShift:(newDepth-nPlanesUsed).

                        outBitCount := outBitCount + newDepth.

                        outBitCount >= 8 ifTrue:[

                            data at:dstIndex put:((data at:dstIndex) bitOr:outBits).

                            dstIndex := dstIndex + 1.

                            outBitCount := 0.

                            outBits := 0.

                        ].

                        inMask := inMask rightShift:1.

                        inMask == 0 ifTrue:[

                            inMask := 16r80.

                            srcIndex := srcIndex + 1.

                        ].

                    ].

                ].

                depth := newDepth.

                "/ rgbi colormap.

self halt.

            ] ifFalse:[

                self halt.

            ].

        ].    

    ].

"/    sourceBytesPerRow ~~ (((width * depth) + 7) // 8) ifTrue:[

"/        "/ have to compress - above code reads sourceBytesPerRow

"/        "/ (to keep in sync with RLE); but we want width bytesPerRow in the image data.

"/        "/ Can compress in the data-area; leftover pixels are simply ignored

"/        "/ by other image processing code

"/        "/

"/        1 to:nPlanes do:[:planeNr |

"/            |dst|

"/

"/            dst := planeData at:planeNr.

"/

"/            dstIndex := width + 1.

"/            srcIndex := sourceBytesPerRow + 1.

"/            2 to:height do:[:row |

"/                dst replaceFrom:dstIndex to:dstIndex+width-1 with:dst startingAt:srcIndex.

"/                dstIndex := dstIndex + width.

"/                srcIndex := srcIndex + sourceBytesPerRow

"/            ]

"/        ].

"/    ].

!

readRestAfterHeader

    "read an raw image in pcx format from aStream.

     The header has already been read into the header argument."

    | version compression xmin ymin xmax ymax

      paletteType 

      byte        "{Class: SmallInteger }" 

      nMaxPad|

    "/ typedef struct {                         /*header for PCX bitmap files*/

    "/    unsigned char       signature;          /*1 PCX file identifier */

    "/    unsigned char       version;            /*2 version compatibility level */

    "/    unsigned char       encoding;           /*3 compression method */

    "/    unsigned char       bitsperpix;         /*4 bits per pixel, or depth */

    "/    unsigned short      Xleft;              /*5 X position of left edge */

    "/    unsigned short      Ytop;               /*7 Y position of top edge */

    "/    unsigned short      Xright;             /*9 X position of right edge */

    "/    unsigned short      Ybottom;            /*11 Y position of bottom edge */

    "/    unsigned short      Xscreensize;        /*13 X screen res of source image */

    "/    unsigned short      Yscreensize;        /*15 Y screen res of source image */

    "/    unsigned char       PCXpalette[16][3];  /*17 PCX color map */

    "/    unsigned char       reserved1;          /*17+48 should be 0, 1 if std res fax */

    "/    unsigned char       planes;             /*66 bit planes in image*/

    "/    unsigned short      linesize;           /*67 byte delta between scanlines */

    "/    unsigned char       paletteinfo;        /*69 paletteType */

    "/                                                /*0 == undef

    "/                                                  1 == color

    "/                                                  2 == grayscale*/

    "/    unsigned char reserved2[58];            /*70 fill to struct size of 128*/

    "/ } PCX_HEADER;

    version := header at:2.

    "/    'version=' print. version printNL.

    compression := header at:3.

    "/    'compression=' print. compression printNL.

    (#(0 1) includes:compression) ifFalse:[

        ^ self fileFormatError:'unknown compression'.

    ].

    depth := header at:4.

    "/    'depth=' print. depth printNL.

    nPlanes := header at:66.

    "/    'planes=' print. nPlanes printNL.

    sourceBytesPerRow := header wordAt:67 MSB:false.

    "/    'srcBytesPerRow=' print. srcBytesPerRow printNL.

    paletteType := header at:69.

    xmin := header wordAt:5 MSB:false. 

    ymin := header wordAt:7 MSB:false.

    xmax := header wordAt:9 MSB:false. 

    ymax := header wordAt:11 MSB:false.

    width := (xmax - xmin + 1).

    height := (ymax - ymin + 1).

    "/    'width=' print. width printNL.

    "/    'height=' print. width printNL.

    "

     although it would be easy to implement ...

     I have no test pictures for other formats.

     So its not (yet) implemented

    "

    ((#(1 2 4 8) includes:depth) "and:[nPlanes == 1]") ifFalse:[

        "/        'PCXReader: depth: ' errorPrint. depth errorPrint. 

        "/        ' planes:' errorPrint. nPlanes errorPrintNL.

        ^ self fileFormatError:'can only handle depth''s 1,2,4 or 8'.

    ].

    (nPlanes between:1 and:4) ifFalse:[

        ^ self fileFormatError:'can only handle 1 to 4 planes'.

    ].

    self reportDimension.

    "/ precompute a first guess at the photometric;

    "/ warning: might be changed by readCompressedData

    paletteType == 2 ifTrue:[

        photometric := #blackIs0.

    ] ifFalse:[

        depth == 1 ifTrue:[

            photometric := #blackIs0.

        ] ifFalse:[    

            photometric := #palette.

        ].

    ].

    compression == 1 ifTrue:[

        self readCompressedData

    ] ifFalse:[

        self readUncompressedData

    ].

    "/ warning: depth might be changed by readCompressedData

    depth == 24 ifTrue:[

        samplesPerPixel := 3.

        bitsPerSample := #( 8 8 8 ).

        photometric := #rgb.

    ] ifFalse:[    

        depth == 32 ifTrue:[

            samplesPerPixel := 4.

            bitsPerSample := #( 8 8 8 8).

            photometric := #rgba.